((:vis "S"
  :pos  #c(500 500)
  :dir  #c(0 -0.001)
  :mass 3000)
 (:vis "E"
  :pos  #c(700 500)
  :dir  #c(0  2.75)
  :mass 2)
 (:vis  "L"
  :pos  #c(600.0 326.78998)
  :dir  #c(2.3815699 1.375)
  :mass 0.001))